Understanding the LCD Monitor Start Circuit

 

Most of the LCD Monitor has a Start Circuit to control the voltage from the power supply to the supply pin of Inverter IC. The main control signal comes from the Main board and the voltage is from 0 and few Volts (2- 5 Volts).

If the signal is Zero Volts, then the inverter IC would not receive any supply voltage from the power supply and if the signal is 2 Volts (On) then the inverter IC would be “On” and the high voltage transformer would energized and the backlights will light up.

The Start Circuit is a good starting point to diagnose why the LCD Monitor has no display, display shutdown and intermittent no display problem.